1. Field of the Invention
This invention relates to the field of electronic devices and, in particular, to systems and methods for operating a display device of a portable device.
2. Description of Related Art
Electronic portable and non-portable devices, such as computers and cell phones, are becoming increasingly common. Such portable devices have grown more complex over time, incorporating many features including, for example, MP3 player capabilities, web browsing capabilities, capabilities of personal digital assistants (PDAs) and the like.
The battery life of these portable devices, however, can be limited. Often, the primary draw of battery power is the display device for these portable devices and, in particular, the backlight, which can be used to illuminate the display device. The display device may also be a significant draw of power for non-portable electronic devices. The backlight may provide a background light or color over which text, pictures and/or images are displayed. In many current portable devices, an exemplary process 10 for illuminating the display is shown in FIG. 1A. In this process, the backlight is activated (e.g. turned on to generate light) when a user enters a key input into the electronic device as shown in operation 12. A timer is started at operation 14 in response to activating the backlight, and the electronic device determines, at operation 16, whether a time out of the timer has occurred. If the electronic device receives a user key input at operation 18, the timer restarts (in operation 14) and the process continues as described above. If the electronic device does not receive a user input while the timer is counting, the time out will occur, and the backlight is deactivated at operation 19.
Some of these electronic devices may also include multiple sensors which are used to detect the environment or context associated with these electronic devices. For example, U.S. patent application publication no. 2005/0219228 describes a device which includes many sensors, including a proximity sensor and a light sensor. The outputs from the sensors are processed to determine a device environment or context. The light sensor detects ambient light levels and the proximity sensor detects a proximity to an object, such as a user's ear or face. In this case, there are two separate sensors which require two openings in the housing of the device. This is shown in FIG. 1B, which shows a device 20. The device 20 includes a proximity sensor 22 mounted on a surface of the device 20 and an ambient light sensor 24 also mounted on the surface of the device 20. Each of these sensors is distinct from the other, and separate openings in the surface are needed for each sensor.